Israeli energy company Innowattech has created a new type of road that generates electricity as cars drive on it:

The supercharged surface is embedded with piezoelectric crystals, which transform kinetic energy from passing vehicles into an electrical current. With widespread adoption, the technology could feed energy back into the nation’s burgeoning electric vehicle grid, transforming congested roadways into a clean green source of energy.

The amount of electricity produced isn't that much (400 kilowatts per kilometer or 645/mi), and there's no mention on how cost effective it would be. But given the sheer amount of roadways we have (the US has over 4 million miles of roads and streets in its highway system alone), it's an interesting albeit niche approach to generate electricity.

from Innowattech's site: "The generators are placed under the upper asphalt layer. The generators possess the same elasticity as the asphalt, and therefore, provide the same resistance to the wheels as asphalt".Looks like a nice solution!

The energy output from the system comes from somewhere. Now, just where does it come from, you ask? Well, you should ask.

If it generates electrical energy from the kinetic energy of passing cars, then it reduces the kinetic energy of those passing cars in the process, which means they slow down. So, those passing cars burn must burn fuel at a higher rate to keep from slowing down. Make no mistake about it; the source of energy is the fuel in the tanks of those passing cars.

This is not a "clean green source of energy", it is simply a very poor way of converting gasoline and diesel fuel into electrical energy. It obeys the laws of physics. Deal with it.